Glucose determination method had gain significant interest from the industry for a fast and efficient response especially in the medical area for diabetes patient. Reduced graphene oxide (RGO) had been reported to help and improve the sensitivity of a sensor. The investigation for the optimum pH concentrations using FESEM, EDX, XRD analysis and Raman spectroscopy indicate that the pH 9 was suited to be deposited on the SPGE. In addition to that, different number of cycles during electrodeposition process was employed. Electrochemical impedance spectroscopy (EIS) was used to investigate the charge transfer resistance for each cycle. All the deposited RGO on screen-printed gold electrode (SPGE) was being compared to the bare SPGE to confirmed that the electrodeposition of RGO could decrease the charge transfer resistance. For the detection of glucose, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) was used. 10 cycles deposition of RGO shows the highest sensitivity of 1.0525 μA·mM−1·cm−2 in the detection of glucose compared to the other cycles. The ease of use and scalability of the electrodeposition technique may make it easier to build upon the results of this work and produce glucose sensors that are more widely available and less expensive.
Titanium dioxide (TiO 2 ) is one of the most investigated metal oxides due to the wide range of applications such as photocatalysts. Photocatalytic activity will increased when the surface area is higher. Hence, this research focus on the surface topography and roughness of nanostructured TiO 2 films characterized by atomic force microscopy (AFM) in order to obtain thin films with the optimum roughness for photocatalytic activity. TiO 2 thin films were prepared by spin coating method at room temperature. The TiO 2 solutions of 0.1-0.2 M were synthesized from titanium butoxide in ethanol. TiO 2 films were deposited on the silicon substrates and annealed at 450°C. The results shown when the film was annealed, the grain were clearly observed. The grain size and the roughness increased when the film were annealed at high temperature. 0.2 M of TiO 2 thin film exhibit the higher roughness with Ra and RMS values were 51.29 and 78.90 nm, respectively.
Study on Ion Sensitive Field Effect Transistor (ISFET) based on multi-finger gate design is presented. Mf-ISFET was fabricated by using commercial submicron 1.0 mum CMOS technology and deposited with PECVD Si 3 N 4 as a sensing membrane. The electrical data such as IdVd and IdVg of ISFET are measured to identify the behaviours of ISFET. Furthermore, the evaluation test on ISFET performance such as transient analysis and hysteresis is also done and discussed in this paper. Based on experimental result gained, better performance of ISFET can be archived by ldquoconditioningrdquo the ISFET before applying it as a sensor.
Tantalum is a potential material for metal anodizing, which enables the fabrication of ideal nanostructured Ta 2 O 5 . This project planned to employ Ta 2 O 5 , an anodized metal oxide, as a chemical sensor application. In the field of Ta 2 O 5 research, there is a lack of investigation into Ta 2 O 5 efficacy for the detection of engine oil deterioration. In this project, the objective is to fabricate Ta 2 O 5 nanotubular as sensing layers for the detection of engine oil deterioration. The Ta 2 O 5 sensor was fabricated through the anodization synthesis method and was then tested with 2, 4, 7, 10, and 12 pH buffer solutions. Anodization is very reliable for building nanostructures as it is easy to be manipulated. Samples were characterized using field emission scanning electron microscope (FESEM) for surface morphology and structural analysis, and their crystalline properties by X-ray diffraction (XRD). The output voltage was plotted over time, and the pH sensitivity of anodized Ta 2 O 5 was reported. As the result, the sensitivity sensor obtained for both 30 min and 60 min anodized samples were 31.616 mV/pH and 24.591 mV/pH, respectively, while the response time was obtained for rise time and fall time was 20 seconds and 90 seconds, respectively.
This work reports the characterization of UV sensor based on nanomoss Nb2O5 films. Nb2O5 has been synthesized by hydrothermal etching reaction of niobium foil in fluoride ion based solution. The morphological and structural of nanomoss Nb2O5 are investigated using FESEM and XRD techniques to determine the properties of the film. From UV characterization, the UV sensor has exhibited good photosensitivity of 2.0 when exposed under turn on/off of UV light.
Nanoporous Nb2O5 has been previously demonstrated to be a viable electrochromic material with strong intercalation characteristics. Despite showing such promising properties, its potential for optical gas sensing applications, which involves the production of ionic species such as H+, has yet to be explored. Nanoporous Nb2O5 can accommodate a large amount of H+ ions in a process that results in an energy bandgap change of the material which induces an optical response. Here, we demonstrate the optical hydrogen gas (H2) sensing capability of nanoporous anodic Nb2O5 with a large surface-to-volume ratio prepared via a high temperature anodization method. The large active surface area of the film provides enhanced pathways for efficient hydrogen adsorption and dissociation, which are facilitated by a thin layer of Pt catalyst. We show that the process of H2 sensing causes optical modulations that are investigated in terms of response magnitudes and dynamics. The optical modulations induced by the intercalation process and sensing properties of nanoporous anodic Nb2O5 shown in this work can potentially be used for future optical gas sensing systems.
This paper discuss the characterization and the performance of two types of ISFET, which have different gate design. Isfet5 has single gate while Isfet7 has multi-finger gate. The characterization of ISFET is analyzed from the IdVd and IdVg curve, and by measuring the threshold voltage, Vth and response-time of ISFET in order to determine the sensitivity of ISFET. Beside, the hysteresis of ISFET is also measured during the experiment. The Vth value extracted from IdVg curve shows that Isfet7 has higher sensitivity compared to Isfet5. While from the response-time, Isfet5 has better sensitivity than Isfet7. In term of hysteresis effect, Isfet7 has less effect of hysteresis compared to Isfet5. However, from the correlation between sensitivity and pH value graph, based on Vth value and response-time, both graphs conclude that Isfet5 has more linear profile with regression value, R 2 more than 0.9960.
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